香蕉束顶病毒研究进展

香蕉束顶病毒(Bananabunchytopvirus,BBTV)是引起香蕉束顶病害(Bananabunchytopdisease,BBTD)的病毒,它严重地危害了香蕉的生产。综述了近年来香蕉束顶病毒的分离提纯方法,株系划分以及分类地位,较为全面的介绍了BBTV病毒基因组分结构和各组分编码蛋白的功能等,并提出了目前需要进一步澄清的问题。     

感染束顶病后香蕉过氧化物酶和多酚氧化酶活性变化

香蕉束顶病株的过氧化物酶和多酚氧化酶的活性变化均呈单峰曲线,两者在香蕉束顶病毒侵染前期被诱导活性显著提高,接种后２１和２８ｄ最高,４２ｄ后则都比健株低,侵染前期ＢＢＴ在体内的运转受抑,接种叶在接种后２８ｄ病毒含量提高,而顶叶则在３ｄ后为最高。     

感染束顶病后香蕉过氧化物酶和多酚氧化酶活性变化(简报)

香蕉束顶病株的过氧化物酶（POD）和多酚氧化酶（PPO）的活性变化均呈单峰曲线，两者在香蕉束顶病毒（BBTV）浸染前期被诱导活性显著提高，接种后21和28d最高，42d后则都比健株低。侵染前期BBTV在体内的运转受抑，接种叶在接种后28d病毒含量最高，而顶叶则在35d后为最高。     

香蕉束顶病毒的纯化及理化特性

从具有典型香蕉束顶病(BBTD)症状的香蕉病组织中提纯了香蕉束顶病毒(Banana bunchy top virus,BBTV)。电镜下可观察到直径为18nm的球形病毒颗粒。最高紫外吸收在255nm,最低紫外吸收在240nm,A_(260)/A_(280)为1.30。用标准BBTV抗体通过ECL-Western转印法测定其外壳蛋白分子量为21kDa。其核酸经DNaseI、RNaseA和Mung Bean Nuclease分析,表明是约1kb的ssDNA。结果与国外文献报道一致。     

香蕉束顶病毒复制酶基因克隆及转基因表达

以广州市郊获得的香蕉束项病毒(BBTV)的DNA为模板,进行PCR扩增得到香蕉束项病毒复制酶基因的1.1 kb DNA.所获得的DNA序列与澳大利亚的BBTV序列的同源性达90%,这部分序列编码香蕉束顶病毒复制酶基因的羧基端.将改造的BBTV复制酶基因克隆到pBll21的CaMV 35S和NOS终止序列之间,构建表达载体,并采用基因枪轰击香蕉试管苗生长点组织的方法,经PCR检测和Westem blot分析,获得4株具有BBTV复制酶基因整合表达的To代转基因香蕉.转基因植株的抗病性正在检测之中.     

植物病毒:对微繁殖的危害及其控制

目前:组织培养被广泛地用作植物快速增殖和种质传播的一种有效方法。然而,它可能会通过侵染培养物或侵染组织培养物衍生的植株的传播而将植物病毒大规模扩散。澳大利亚研究人员R. A. Drew等人已从感染有香蕉束顶病毒(BBTV)(在澳大利亚、亚洲和非洲的一种严重侵染香蕉的病毒)的香蕉树外植体中微繁殖出植株。这些植株尚未表现出病毒侵染症状,与未侵染的对照产生的微繁殖植株没有区别。然而,经16个月的培养后产生的植株有75％表现出BBTV侵染的症状。     

香蕉线条病毒病研究进展

香蕉是重要的经济作物和粮食作物,广泛种植于热带、亚热带地区.在我国的广东、福建、海南、广西和云南等地均有大面积种植,产销量一直居南方四大水果之冠.然而,近年来,许多病毒病害成为香蕉生产发展的主要限制因素,主要包括香蕉束顶病毒(banana bunchy top virus,BBTV)、香蕉线条病毒(banana streak virus,BSV)、香蕉苞片花叶病毒(banana bract mosaic virus,BBrMV)、黄瓜花叶病毒(cucumber mosaic virus,CMV)等引起的病害.     

香蕉束顶病毒研究进展

香蕉束顶病毒（Bananabunchytopvirus,BBTV）引起的香蕉束顶病（Ban。bu。bytoPdisease）是香蕉一种严重的病毒病害。迄今此病已普遍分布在世界许多产区,诸如：亚洲、非洲、澳大利亚、南太平洋一些岛屿以及美国的夏威夷等地区［‘－’l。在我国广东、广西、福建、云南等省的部分产区的发病率约占5—25％左右,严重地块已发展到毁灭性程度卜］。1987年Dale曾对世界香蕉种植的地理分布和BBTV的流行范围之间的关系、病株症状、病毒病原学、流行病学、病毒诊断方法以及病害的控制作过全面的综述【门。然而由于BBTV存在于寄主植物的韧皮…     

利用超低温保存方法脱除香蕉束顶病毒的研究

香蕉束顶病毒(BBTV)是香蕉生产中的严重病害之一,主要通过感病材料和香蕉交脉蚜等昆虫进行传播,目前尚无有效防治方法.本研究以感染BBTV的巴西蕉(Musa AAA Cavendish)为材料,研究了感染BBTV的巴西蕉离体再生和超低温保存技术条件,表明离体茎尖在MS+6-BA 4 0 mg/L+NAA 0 4 mg/L的培养基上分化不定芽较好;采用玻璃化法超低温保存技术保存带有BBTV的香蕉茎尖,再生后植株BBTV脱除率达到60 6%,而常规的茎尖培养对BBTV的脱除率仅为26 7%.     

香蕉束顶病株的细胞超微结构的电镜观察(简报)

植物病毒侵染对寄生植物的影响,不仅表现在寄主植物的生理生化代谢方面,而且使寄主的组织细胞结构也发生改变,并最终导致病毒感染所特有的症状产生［１－３］。研究病毒感染后寄主的细胞及亚细胞结构的变化,有助于了解病毒病在细胞形态结构水平上的病变机制［４］。香蕉束顶病是由香蕉束顶病毒（ＢａｎａｎａＢｕｎｃｈｙＴｏｐＶｉｒｕｓ,ＢＢＴＶ）侵染引起的一种重要病毒病,在世界各主要香蕉产区均有发生［５］,对我国的香蕉种植危害也很大。近年来,对ＢＢＴＶ的分子生物学［６］及其侵染后引发的寄主次生代谢酶类和内源激素的变…     

特异扩增BBTV基因组Ⅲ、Ⅳ、Ⅰ编码区部分序列及其在检测中的应用

香蕉束顶病(BBTD)是香蕉植株的一种毁灭性病害,正在世界(包括中国)的许多香蕉种植区蔓延[1～7].其病原物为香蕉束顶病毒(Banana Bunchy Top Virus,BBTV),被列为我国第三类检疫对象.目前生产上主要采用培育脱毒组培苗来防治BBTD的发生,因此建立一种能快速、灵敏、特异地检测BBTV的方法就显得很重要.国内现在大多采用ELISA方法,但其灵敏度不够高,且需要制备特异性强的抗血清,否则较易出现假阳性.     

Two Circular Single-stranded DNAs Associated with Banana Bunchy Top Virus

Nucleic acids extracted from partially purified banana bunchy top virus (BBTV) consisted of 20 Kb DNA, 0.9–1.1 Kb DNA and 0.3 Kb RNA. Partially purified BBTV preparations predigested with DNase and RNase before particle disruption and nucleic acid isolation yielded only the 0.9–1.1 Kb DNA, but no corresponding nucleic acid band was obtained in total nucleic acid isolated from healthy banana tissue. Analysis of two BBTV cDNA clones showed that clone 1 consisted of 287 nucleotides and clone 2 contained a 1.0 Kb DNA insert. Clone 1 is not part of clone 2. When two pairs of primers, each pair in opposite orientation were used to amplify BBTV DNA by PCR using the total DNA from diseased banana tissues or DNA encapsidated in BBTV particle as the template, a DNA product of 1.1 Kb was generated by both, results indicating that the BBTV DNAs are circular. Additional results suggested that BBTV contained at least two circular ssDNAs designated BBTV cssDNA I (containing clone 1 nucleotide sequence) and BBTV cssDNA II (containing clone 2 nucleotide sequence).     

Two Circular Single-stranded DNAs Associated with Banana Bunchy Top Virus

Nucleic acids extracted from partially purified banana bunchy top virus (BBTV) consisted of 20 Kb DNA, 0.9-1.1 Kb DNA and 0.3 Kb RNA. Partially purified BBTV preparations predigested with DNase and RNase before particle disruption and nucleic acid isolation yielded only the 0.9-1.1 Kb DNA, but no corresponding nucleic acid band was obtained in total nucleic acid isolated from healthy banana tissue. Analysis of two BBTV cDNA clones showed that clone 1 consisted of 287 nucleotides and clone 2 contained a 1.0 Kb DNA insert. Clone 1 is not part of clone 2. When two pairs of primers, each pair in opposite orientation were used to amplify BBTV DNA by PCR using the total DNA from diseased banana tissues or DNA encapsidated in BBTV particle as the template, a DNA product of 1.1 Kb was generated by both, results indicating that the BBTV DNAs are circular. Additional results suggested that BBTV contained at least two circular ssDNAs designated BBTV essDNA I (containing clone 1 nucleotide sequence) and BBTV, cssDNA II (containing clone 2 nucleotide sequence).     

Use of polymerase chain reaction (PCR) to study transmission of banana bunchy top virus by the banana aphid (Pentalonia nigronervosa)

Banana bunchy top virus (BBTV) is a ssDNA virus transmitted by the banana aphid, ( Pentalonia nigronervosa ). A polymerase chain reaction (PCR) assay was used to study BBTV transmission efficiency, to determine the minimum acquisition-access period, the minimum inoculation-access period, the retention time, and to examine the possibility of transovarial transmission in this vector. BBTV was acquired by banana aphids within 4 h and was transmitted within 15 min feeding. On average, more than 65% of single viruliferous adult aphids transmitted BBTV. The aphids retained BBTV for their adulthood of 15–20 days. None of the 131 offspring from adult aphids reared on infected bananas were BBTV positive. Aphid transmission experiments were conducted to determine if taro and gingers are hosts of BBTV. None of the 87 taro and ginger plants exposed to aphid inoculation were infected by BBTV. The BBTV-free status of these plants was verified by PCR assay for 6 months post-inoculation. In addition, none of the taro and ginger samples collected from fields adjacent to BBTV-infected banana plants tested positive for BBTV.     

Screening of banana bunchy top virus through multiplex PCR approach

Bunchy top disease caused by the banana bunchy top virus (BBTV) is a serious disease in hill banana. Detection of the BBTV infection in the planting material could help in the effective management of the disease. An attempt was made to develop a sensitive polymerase chain reaction (PCR) and multiplex PCR-based method for detection of BBTV in hill banana. DNA was isolated from the experimental plants at third and sixth months after planting. Multiplex PCR was done with Coat Protein (CP) and Replicase (Rep) gene-specific primer, and banana ethylene insensitive like protein (EISL) primer as internal control to identify failure in PCR reaction. This study revealed that multiplex PCR is effective for BBTV screening in hill banana with the advantage of overcoming the false positive in PCR amplification.     

The transmission of banana bunchy-top virus in micropropagated bananas

Plants were established in vitro from banana bunchy0top virus (BBTV) infeeted plants. Explants containing either vegetative shoot apices or terminal floral apices were used to initiate cultures. Plants multiplied in culture were indistinguishable from non-infected (control) plants and lacked characteristic symptoms of BBTV infection. After 16 months in culture plants were established in the glasshouse and after 1 month in pots some plants started to show symptoms of the disease. After a further 5 months, 73% of the plants showed characteristic symptoms of the disease while 27% were symptomless and similar in appearance to control plants. These plants have been grown to maturity in the field without showing recognizable symptoms. This study demonstrates that BBTV can be transmitted in an apparently symptomless condition in culture and has important consequences for the dissemination of banana germplasm within Australia and internationally.     

香蕉束顶病毒基因克隆和序列分析

对香蕉束顶病毒（ＢＢＴＶ）中国分离株ＤＮＡ组份Ｉ（ＤＮＡ－１）、外壳蛋白（ＣＰ）和运转蛋白（ＭＰ）基因进行了克隆和序列分析。ＢＢＴＶＤＮＡ－１含有１１０３个核苷酸,与南太平洋和亚洲分离株分别有８７％－８８％ ９６．９－９８％的核苷酸序列同源性。由ＤＮＡ－１编码的复制酶含有１８６个在酸残基。与南太平洋和亚洲分离株分别有８４．４％－９５．８％和９７．６％、９８．０％的氨基酸序列同源性。外壳蛋白基因由５     

Purification and Characterization of Banana Bunchy Top Virus

Abstract Banana bunchy top virus (BBTV) was successfully purified by a procedure which included pulverizing diseased tissues frozen in liquid nitrogen, clarification of the extract with chloroformbutanol, concentration of the virus by cycles of differential centrifugation, stirring and incubating at 4°C followed by a second cycle of differential centrifugation and sucrose density gradient centrifugation. The concentrations of BBTV obtained from leaf blades and midribs plus petioles were up to 0.34 and 0.56mg/kg tissue, respectively. The virus concentration was highest in diseased leaves collected from October to December, and lowest in those collected from June to September. BBTV is a luteovirus (particles 20– 22 nm in diameter), preparations of which have maximum absorbance at 257 nm, minimum absorbance at 240 nm and a A260/280 ratio of 1.46. The relative molecular mass (M_r) of BBTV coat protein subunit is 21,000, and that of its ssRNA is 2.0 × 10⁶.